1. Field of the Invention
The present invention relates to a disk reproducing apparatus for reproducing a video and sound signal recorded on an optical disk such as a DVD (Digital Versatile Disc) or a CD (Compact Disc), and more specifically relates to a disk reproducing apparatus capable of reducing noise associated with rotation of an optical disk to reproduce the optical disk and reproducing the optical disk without discontinuity in video and sound in reproduction even when a read error of a video and sound signal occurs during reproduction of the optical disk.
2. Description of the Related Art
A disk reproducing apparatus for reproducing an optical disk such as a DVD or a CD is constructed so that an error of a video and sound signal read from the optical disk can be corrected based on an error-correcting code added to the video and sound signal to reproduce the video and sound signal even when small dirt or flaw, etc. is present on a signal record surface of the optical disk. However, in case that a read error of a video and sound signal occurs and the error of the video and sound signal cannot be corrected due to external factors such as shock or vibration or internal factors such as dirt or flaw on the signal record surface of the optical disk, there was a problem that reading of the video and sound signal must be retried and when retries of the video and sound signal are repeated frequently, data of buffer memory in which the video and sound signal reproduced is temporarily stored is lost and the video and sound signal cannot be outputted at a constant transfer rate and video and sound in reproduction discontinue. Also, when an optical disk is rotated at high speed and a video and sound signal recorded on the optical disk is reproduced in a high-speed mode, a reproduction speed of the video and sound signal improves, but there was a problem that mass buffer memory is required in order to temporarily store the video and sound signal reproduced and noise such as rotation noise of the optical disk, vibration noise due to side runout or eccentricity of the optical disk or wind noise due to rotation of the optical disk increases as compared with the case of rotating the optical disk at low speed. Also, when an optical disk is rotated at low speed and a video and sound signal recorded on the optical disk is reproduced in a low-speed mode, capacity of buffer memory in which data of the video and sound signal reproduced is temporarily stored can be decreased and noise such as rotation noise of the optical disk, vibration noise due to side runout or eccentricity of the optical disk or wind noise due to rotation of the optical disk can be reduced, but there was a problem that when a read error of the video and sound signal occurs, a rotational speed of the optical disk is low and so the number of retries of reading of the video and sound signal of a sector in which the read error of the video and sound signal occurs decreases and data of the buffer memory in which the video and sound signal reproduced is temporarily stored is lost and the video and sound signal cannot be outputted at a constant transfer rate and video and sound in reproduction discontinue.
As a related art, there was means constructed so that when a read error of a video and sound signal occurs in the case of reproducing information recorded on a record medium, by retries of reading of the video and sound signal, a rotational speed of the record medium is decelerated to perform reproduction and it is checked whether or not there is a mechanism for correcting the read error of the video and sound signal in a minimum unit block of information about the record medium and time for deciding whether or not the rotational speed of the record medium is returned is determined based on the check result and the rotational speed of the record medium is returned to the original rotational speed before the deceleration when subsequent information can be reproduced without further decelerating the rotational speed of the record medium by retries of the reading of the video and sound signal during the time determined (for example, see JP-A-2002-251818).